Snake Venom Polypeptides Research Articles

Design and characterization of crotamine-functionalized gold nanoparticles

This paper describes the development of a facile and environmentally friendly strategy for supporting crotamine on gold nanoparticles (GNPs). Our approach was based on the covalent binding interaction between the cell penetrating peptide crotamine, which is a snake venom polypeptide with preference to penetrate dividing cells, and a polyethylene glycol (PEG) ligand, which is a nontoxic, water-soluble and easily obtainable commercial polymer. Crotamine was derivatized with ortho-pyridyldisulfide-polyethyleneglycol-N-hydroxysuccinimide (OPSS-PEG-SVA) cross-linker to produce OPSS-PEG-crotamine as the surface modifier of GNP. OPSS-PEG-SVA can serve not only as a surface modifier, but also as a stabilizing agent for GNPs. The successful PEGylation of the nanoparticles was demonstrated using different physicochemical techniques, while the grafting densities of the PEG ligands and crotamine on the surface of the nanoparticles were estimated using a combination of electron microscopy and mass spectrometry analysis. In vitro assays confirmed the internalization of these GNPs, into living HeLa cells. The results described herein suggest that our approach may serve as a simple platform for the synthesis of GNPs decorated with crotamine with well-defined morphologies and uniform dispersion, opening new roads for crotamine biomedical applications.

New drug developments of snake venom polypeptides and progress

The value of snake venom polypeptides in clinical application has drawn extensive attention, and the development of snake polypeptides into new drugs with anti-tumor, anti-inflammatory, antithrombotic, analgesic or antihypertensive properties has become the recent research hotspot. With the rapid development of molecular biology and biotechnology, the mechanisms of snake venom polypeptides are also gradually clarified. Numerous studies have demonstrated that snake venom polypeptides exert their pharmacological effects by regulating ion channels, cell proliferation, apoptosis, intracellular signaling pathway, and expression of cytokine as well as binding to relevant active sites or receptors.

Effects of Snake Venom Polypeptides on Central Nervous System

The nervous system is a primary target for animal venoms as the impairment of its function results in the fast and efficient immobilization or death of a prey. There are numerous evidences about effects of crude snake venoms or isolated toxins on peripheral nervous system. However, the data on their interactions with the central nervous system (CNS) are not abundant, as the blood-brain barrier (BBB) impedes penetration of these compounds into brain. This updated review presents the data about interaction of snake venom polypeptides with CNS. Such data will be described according to three main modes of interactions: - Direct in vivo interaction of CNS with venom polypeptides either capable to penetrate BBB or injected into the brain. - In vitro interactions of cell or sub-cellular fractions of CNS with crude venoms or purified toxins. - Indirect effects of snake venoms or their components on functioning of CNS under different conditions. Although the venom components penetrating BBB are not numerous, they seem to be the most suitable candidates for the leads in drug design. The compounds with other modes of action are more abundant and better studied, but the lack of the data about their ability to penetrate BBB may substantially aggravate the potentials for their medical perspectives. Nevertheless, many such compounds are used for research of CNS in vitro. These investigations may give invaluable information for understanding the molecular basis of CNS diseases and thus lay the basis for targeted drug design. This aspect also will be outlined in the review.

Competitive Interactions of Collagen and a Jararhagin-derived Disintegrin Peptide with the Integrin α2-I Domain

Integrin alpha2beta1 is a major receptor required for activation and adhesion of platelets, through the specific recognition of collagen by the alpha2-I domain (alpha2-I), which binds fibrillar collagen via Mg(2+)-bridged interactions. The crystal structure of a truncated form of the alpha2-I domain, bound to a triple helical collagen peptide, revealed conformational changes suggestive of a mechanism where the ligand-bound I domain can initiate and propagate conformational change to the full integrin complex. Collagen binding by alpha2-I and fibrinogen-dependent platelet activity can be inhibited by snake venom polypeptides. Here we describe the inhibitory effect of a short cyclic peptide derived from the snake toxin metalloprotease jararhagin, with specific amino acid sequence RKKH, on the ability of alpha2-I to bind triple helical collagen. Isothermal titration calorimetry measurements showed that the interactions of alpha2-I with collagen or RKKH peptide have similar affinities, and NMR chemical shift mapping experiments with (15)N-labeled alpha2-I, and unlabeled RKKH peptide, indicate that the peptide competes for the collagen-binding site of alpha2-I but does not induce a large scale conformational rearrangement of the I domain.

Snake Venom Polypeptides Affecting the Central Nervous System

There are numerous evidences about the effects of crude snake venoms or isolated toxins on the peripheral nervous system. However, the data on their interactions with the central nervous system (CNS) are not so abundant, since the blood-brain barrier (BBB) impedes penetration of these compounds into the brain. There are several reviews describing the interactions of particular classes of snake venom polypeptides with components of the CNS; however, no general systematics of such interactions was done. This review is the first attempt to consolidate the data about the interaction of snake venom polypeptides with the CNS. Such data will be described according to three main modes of interactions: - Direct in vivo interaction of the CNS with venom polypeptides capable to penetrate BBB. - In vitro interactions of isolated components of the CNS with crude venoms or purified toxins. - Indirect effects of snake venoms or their components on functioning of the CNS under normal or pathological conditions. Although the venom components penetrating BBB are not numerous, they seem to be the most suitable candidates for the leads in drug design. The compounds from two other groups are more abundant and better studied, but the fact that the data about their ability to penetrate BBB are still absent may substantially aggravate the potentials for their medical perspectives. Nevertheless, many of these compounds are used as biochemical tools for research of the CNS in vitro. These investigations may give invaluable information for understanding the molecular basis of CNS diseases and thus lay the basis for targeted drug design. This aspect also will be outlined in the review. Keywords: Snake venom, polypeptides, neurotoxins, central nervous system, brain

Expression and characterization of a synthetic protein C activator in Pichia pastoris

Protein C activators are proteases that activate protein C in the mammalian coagulation system. A reptilian protein C activator is a critical component in current functional assays for protein C, its cofactor protein S, as well as for the overall status of the protein C pathway. We have constructed a synthetic gene for a protein C activator, based on a published snake-venom polypeptide sequence. This recombinant protein C activator was expressed in Pichia pastoris as a secreted glycoprotein (ILPCA) using the AOX1 promoter and the α-factor signal sequence. A fermentation protocol was developed that produced about 150 mg/L biologically active ILPCA secreted in the fermented broth. A two-step purification scheme was devised to purify ILPCA to ∼80% purity. The ILPCA produced has an apparent molecular weight of ∼68 kDa and a deglycosilated molecular weight of 28 kDa. Steady-state kinetic analysis reveals that ILPCA activates purified human protein C with a K m of 77 nM and a k cat of 0.39 s −1 . In conclusion, ILPCA is a recombinant protein that can be produced reliably and in large quantities under controlled manufacturing conditions, activates protein C, and can be used in coagulation assays as an alternative to native venom preparations.

Thymopoietin, a thymic polypeptide, specifically interacts at neuronal nicotinic alpha-bungarotoxin receptors.

alpha-Bungarotoxin (alpha-BGT), a snake venom polypeptide, interacts potently and specifically with a nicotinic receptor population in neuronal tissue. However, the identity of this site is unclear, because, unlike at the neuromuscular junction and in electroplax, in nervous tissue the toxin does not block nicotinic cholinergic responses. Therefore, we sought endogenous compounds other than acetylcholine that could interact with the neuronal alpha-BGT site. In the present experiments, thymopoietin, a polypeptide isolated from the thymus, is shown to inhibit potently alpha-BGT binding to brain membranes in a dose-dependent manner (IC50 = 3.1 nM). This effect was not shared by a wide variety of other peptides, including thysplenin, a closely related polypeptide. Thymopoietin did not inhibit the binding of other radioligands known to interact with different populations of cholinergic receptors, such as [3H]nicotine and [3H]methylcarbachol, which bind to nicotinic receptors, or [3H]quinuclidinylbenzilate, which binds to muscarinic receptors. These results show that thymopoietin potently and specifically affects 125I-alpha-BGT binding to brain membranes and suggest that thymopoietin might be an endogenous ligand for alpha-BGT receptors in neuronal tissue.

Involvement of neuronal acceptors for dendrotoxin in its convulsive action in rat brain

Dendrotoxin, a snake-venom polypeptide, is a potent convulsant that facilitates transmitter release apparently by inhibition of voltage-sensitive K+ channels responsible for A-currents. A biologically active 125I-iodinated derivative of this toxin was prepared and used to characterize kinetically homogeneous non-interacting high-affinity acceptors in synaptic membranes from rat cerebral cortex and hippocampus. Binding of radiolabelled toxin from Dendroaspis angusticeps to its membrane acceptor protein was inhibitable by homologous polypeptides from other mamba snakes; most importantly, their rank order of potency was identical with that for their central neurotoxicities in rats, furnishing evidence for involvement of this binding component in the convulsive symptoms observed. Beta-Bungarotoxin, a presynaptically acting neurotoxin whose action on neurotransmitter release at the neuromuscular junction and effects on brain synaptosomes are antagonized by dendrotoxin, was only able to inhibit the binding of the 125I-labelled toxin with low efficacy, although dendrotoxin apparently interacts avidly with the acceptor sites for beta-bungarotoxin. This weak interaction of beta-bungarotoxin with the acceptor was not attributable to its phospholipolytic action. Other neurotoxins and ion-channel antagonists failed to affect the binding of dendrotoxin. The findings presented here, together with recent electrophysiological data, favour the interpretation that dendrotoxin binds to a membrane protein comprising, or closely associated with, this one group of voltage-dependent K+ channels.

Dual effects of the snake venom polypeptide vipoxin on receptors for acetylcholine and biogenic amines in Aplysia neurons

Vipoxin, a 13,000-dalton polypeptide component of Russell's viper venom, has a dual pattern of effects on the responses of voltage-clamped Aplysia neurons to acetylcholine and biogenic amines. Application of low doses of vipoxin by pressure ejection reversibly antagonized all three types of ionic response to acetylcholine and carbachol. The blockade by vipoxin of acetylcholine responses was not prevented by eserine. The order of susceptibility of acetylcholine responses to blockade by vipoxin was Na + > K + > Cl −. Low doses of vipoxin also produced a reversible potentiation of excitatory responses to dopamine with a slower time course of onset and recovery. Inhibitory responses to dopamine (Cl −, K +) and both excitatory and inhibitory responses to histamine and 5-hydroxytryptamine were little affected by vipoxin. Higher doses of vipoxin directly evoked current responses which were always of the same ionic type as that evoked by acetylcholine or carbachol. Responses to cholinergic agonists and vipoxin were both blocked by cholinergic antagonists but not by antagonists of biogenic amine receptors, which reversibly antagonized the responses to amines on the same cell. These results suggest that vipoxin, which has no demonstrated actions on vertebrate acetylcholine receptors, acts as a partial agonist at all three types of acetylcholine receptor in Aplysia neurons. Our observations thus provide evidence for some degree of phylogenetic difference between vertebrate and molluscan acetylcholine receptors.

Serotonin induces a voltage-sensitive calcium current in neurons of Aplysia californica.

Serotonin induces a voltage-sensitive calcium current in neurons of Aplysia californica.T C Pellmar, and D O CarpenterT C Pellmar, and D O CarpenterPublished Online:01 Sep 1980https://doi.org/10.1152/jn.1980.44.3.423MoreSectionsPDF (3 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByReal-Time Measurements of Synaptic Autoinhibition Produced by Serotonin Release in Cultured Leech NeuronsMontserrat G. Cercós, Francisco F. De-Miguel, and Citlali Trueta1 August 2009 | Journal of Neurophysiology, Vol. 102, No. 2Serotonergic Modulation of a Voltage-Gated Calcium Current in Parapodial Swim Muscle From Aplysia brasilianaP. J. Laurienti, and J. E. Blankenship1 March 1997 | Journal of Neurophysiology, Vol. 77, No. 3An enzymatic mechanism for potassium channel stimulation through pertussis-toxin-sensitive G proteinsTrends in Neurosciences, Vol. 15, No. 10Characterization of responses to enkephalins and FMRFamide on B neurons of the cerebral ganglion of AplysiaComparative Biochemistry and Physiology Part C: Comparative Pharmacology, Vol. 99, No. 3Extracellular tumor necrosis factor induces a decreased K+ conductance in an identified neuron of Aplysia kurodaiNeuroscience Letters, Vol. 115, No. 2-3Novel peripheral neurotransmitters in invertebratesPharmacology & Therapeutics, Vol. 41, No. 3Slow synaptic responses mediated by the helix giant serotonin-neurones on identified follower neuronesComparative Biochemistry and Physiology Part C: Comparative Pharmacology, Vol. 91, No. 1In vivo labeling of serotonin-containing neurons by 5,7-dihydroxytryptamine inAplysiaBrain Research, Vol. 426, No. 1The adenylate cyclase rebound response to naloxone in the NG108-15 cellsNeuropharmacology, Vol. 25, No. 8Enkephalin-like substance in Aplysia nervous tissue and actions of leu-enkephalin on single neuronsLife Sciences, Vol. 38, No. 16The ionic mechanism associated with the action of putative transmitters on identified neurons of the snail, Helix aspersaComparative Biochemistry and Physiology Part C: Comparative Pharmacology, Vol. 84, No. 2Acetylcholine responses in snail neurons: Increase and decrease in potassium conductance succeeding inward currentsBrain Research, Vol. 347, No. 2Dual effects of the snake venom polypeptide vipoxin on receptors for acetylcholine and biogenic amines in Aplysia neuronsNeuroscience, Vol. 14, No. 2The modulatory action of 5-hydroxytryptamine on sodium efflux: the barnacle muscle fibre as a model systemComparative Biochemistry and Physiology Part C: Comparative Pharmacology, Vol. 80, No. 2Changes in ionic conductances induced by cAMP in Helix neuronsBrain Research, Vol. 305, No. 1Localization of vitamin D-dependent calcium binding protein in the electrosensory and electromotor system of high frequency gymnotid fishBrain Research, Vol. 301, No. 1The pharmacology of molluscan neuronsProgress in Neurobiology, Vol. 23, No. 1-2Vipoxin both activates and antagonizes three types of acetylcholine response inAplysia neuronsBrain Research, Vol. 278, No. 1-2Modulation of gated ion channels as a mode of transmitter actionTrends in Neurosciences, Vol. 6Control of calcium current in rat sympathetic neurons by norepinephrineBrain Research, Vol. 244, No. 1Voltage-dependent actions of endogenous and exogenous serotonin on identified neuronesComparative Biochemistry and Physiology Part C: Comparative Pharmacology, Vol. 72, No. 2Calcium channels in the neuronal membraneBiochimica et Biophysica Acta (BBA) - Reviews on Biomembranes, Vol. 650, No. 2-3Voltage-dependent current evoked by dopamine and octopamine in AplysiaBrain Research, Vol. 223, No. 2Relationship between two voltage-dependent serotonin responses of molluscan neuronesBrain Research, Vol. 217, No. 1Transmitter control of voltage-dependent currentsLife Sciences, Vol. 28, No. 20Cyclic AMP induces a voltage-dependent current in neurons of Aplysia californicaNeuroscience Letters, Vol. 22, No. 2 More from this issue > Volume 44Issue 3September 1980Pages 423-39 https://doi.org/10.1152/jn.1980.44.3.423PubMed6255107History Published online 1 September 1980 Published in print 1 September 1980 Metrics

Chemical and functional homology of myotoxin a from prairie rattlesnake venom and crotamine from south american rattlesnake venom

Myonecrosis is a serious result of rattlesnake bite and constitutes a persistent clinical problem. In the current study we have isolated crotamine from the venom of Crotalus durissus terrificus to test its ability to cause structural damage to skeletal muscle, and to make direct chemical comparisons with Myotoxin a, a myotoxic polypeptide we recently isolated from prairie rattlesnake ( Crotalus viridis viridis) venom. Disc gel electrophoresis, isoelectric focusing, circular dichroic spectroscopy, and amino acid analysis, all indicated a high degree of chemical similarity. Light microscope histology revealed that crotamine caused vacuolization of skeletal muscle fibers, qualitatively the same as the vacuolization caused by Myotoxin a. The ability of these two basic snake venom polypeptides to cause structural damage to skeletal muscle fibers has significant implications toward more complete understanding of the cause of snake venom-induced myonecrosis.

Blocking action of snake venom polypeptides on cholinergic mechanisms of the leech dorsal muscle

The blocking action of α-polypeptides isolated from the venom ofBungarusmulticinctus andNajanaja siamensis was investigated in experiments on the isolated dorsal muscle of the leech. These neurotoxins (NTs), in a concentration of 1×10−5 g/ml, did not block responses to monoquaternary cholinomimetics (acetylcholine, carbachol, nicotine, monocholine ester of succinic acid). The ability of NT to block responses to biquaternary cholinomimetics depended on the length of their molecule. Only responses to dicholine esters of malonic, succinic and glutaric acids were blocked by NT. Dicholine esters of adipic, pimelic, suberic, azelaic, and sebacic acids retained the whole of their activity after treatment of the leech muscle with NT. The possible causes of the selective action of NT are discussed.

Action of snake venom polypeptides on cholinergic receptors of the isolated rabbit sympathetic ganglion

Action of snake venom polypeptides on cholinergic receptors of the isolated rabbit sympathetic ganglion

The desensitization of postjunctional muscle membrane after intracellular application of membrane stabilizers and snake venom polypeptides

The desensitization of postjunctional muscle membrane after intracellular application of membrane stabilizers and snake venom polypeptides